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/* SPDX-License-Identifier: ISC */
#include <stdbool.h>
#include <stddef.h>
#include <string.h>
#include <errno.h>
#include "service.h"
static bool has_dependencies(service_t *list, service_t *svc)
{
const char *ptr;
int i;
while (list != NULL) {
for (ptr = svc->after, i = 0; i < svc->num_after; ++i) {
if (!strcmp(ptr, list->name))
return true;
ptr += strlen(ptr) + 1;
}
for (ptr = list->before, i = 0; i < list->num_before; ++i) {
if (!strcmp(ptr, svc->name))
return true;
ptr += strlen(ptr) + 1;
}
list = list->next;
}
return false;
}
service_t *svc_tsort(service_t *list)
{
service_t *nl = NULL, *end = NULL;
service_t *svc, *prev;
while (list != NULL) {
/* remove first service without dependencies */
prev = NULL;
svc = list;
while (svc != NULL) {
if (has_dependencies(list, svc)) {
prev = svc;
svc = svc->next;
} else {
if (prev != NULL) {
prev->next = svc->next;
} else {
list = svc->next;
}
svc->next = NULL;
break;
}
}
/* cycle! */
if (svc == NULL) {
if (end == NULL) {
nl = list;
} else {
end->next = list;
}
errno = ELOOP;
break;
}
/* append to new list */
if (end == NULL) {
nl = end = svc;
} else {
end->next = svc;
end = svc;
}
}
return nl;
}
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